A new soil test allows growers to detect the pathogen responsible for causing Fusarium Basal Rot risk in onions.


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Agriculture Horticulture Research and development

Fusarium Basal Rot is an untreatable soil-borne disease costing the UK onion industry approximately £10 million a year

Infected crops show little symptoms until after harvest, when bulbs may begin to rot in storage. In the UK, crop losses can reach 40% with some onion growers losing their entire onion stores to the disease. The disease is caused by the soil pathogen Fusarium oxysporum f. sp. cepae (FOC) – a strain of fungi resident in soil that infects bulb crops via their roots.

The FUSED project

Under the Innovate UK and Defra-funded two-year FUSED project, bioscientists at the University of Warwick developed a DNA-based diagnostic test capable of detecting this pathogen in soil samples, allowing growers to identify disease risk in their fields before planting.

Project lead Professor John Clarkson, Plant Pathologist at the University of Warwick, explained:

“Accurate detection and quantification of Fusarium strains in soil has historically been extremely difficult and has limited growers’ ability to manage their risk of Fusarium basal rot effectively. Through a process of enrichment and DNA extraction, we are now able to confirm how prevalent the FOC pathogen is in a given soil sample.”

“The results come with a traffic light system to indicate how serious the risk to crop may be and the damage it could do, allowing growers to plan their planting accordingly. We encourage all growers in doubt to get in touch with us and book soil testing via the ADAS website to avoid a potentially very costly problem later. Unfortunately, Fusarium Basal Rot remains untreatable for now, but it is no longer unavoidable.”

Ben Collins, Chair of British Onions Producer Association (BOPA) said:

“The UK onion industry has seen a rapid increase in the level of Fusarium over the last 15 years. We’re pleased this new soil test will help growers make informed decisions on cropping prior to planting and in turn help reduce the financial impact caused by this soil borne disease.”

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